Under the alias of Dr Smith, he tried to stop the Sodality from existing, so that hundreds of time sensitives would not be killed by them. After failing to gain the support of the High Executioner in erasing the Sodality from history, the Doctor departed in his TARDIS.

The Doctor set events in motion so the "Child of Time" would gain its full powers and stop the Solidarity's plans. The Doctor left in his TARDIS with the unconscious High Executioner, who was now suffering from amnesia. The Doctor dropped off the High Executioner in 1949, where she called herself by her real name, Emily Blandish, and helped the Doctor defeat Mestizer in his relative past. (PROSE: Child of Time)

The Doctor wore a black coat with green collar, white shirt, a loose collar on the coat, exposing his neck and pronounced throat. He wore a hat and muffler. He was clean shaven on only his chin and lip and had brown hair which was receding. He was gangly but not too tall and had large hands. (PROSE: The Cabinet of Light)

There is a similarity between the Shalka Doctor and this incarnation of the Doctor. However such a similarity is entirely coincidental, as author Daniel O'Mahony worked on this story with no information that a new incarnation of the Doctor would be introduced just months after the publication of his novella. [1]